A mixture comprising an o-ethyldiphenylalkane and a m-ethyldiphenylalkane can be industrially produced in low cost utilizing an alkylation reaction, a disproportionation reaction, a condensation reaction and the like in the presence of an acid catalyst from a raw material such as an alkylbenzene.
Hereby, .alpha.-(m-benzoylphenyl)propionic acid (tradename: Ketoprofen) of a profen analgesic is obtained by a reaction such as a carbonylation from 1-(m-vinylphenyl)-1-phenylethane in Japanese Patent Application Laid-open No. Hei 2-101041. In addition, .alpha.-(m-benzoylphenyl)propionic acid of a profen analgesic is obtained from 1-(m-vinylphenyl)-1-phenylethylene in Japanese Patent Application Laid-open No. Hei 3-31221. Further, in U.S. Pat. No. 4,922,052 (m-vinylphenyl)phenylmethane or the like is produced using a Grignard reagent, and .alpha.-(m-benzoylphenyl)propionic acid (tradename: Ketoprofen) of a profen analgesic is obtained therefrom.
Any of the processes for producing .alpha.-(m-benzoylphenyl)propionic acid (tradename: Ketoprofen) of a profen analgesic from the above-mentioned 1-(m-vinylphenyl)-1-phenylethane, 1-(m-vinylphenyl)-1-phenylethylene, (m-vinylphenyl)phenylmethane is according to a cheap and simple process such as carbonylation or the like. Accordingly, it should be said that 1-(m-vinylphenyl)-1-phenylethane, 1-(m-vinylphenyl)-1-phenylethylene, (m-vinylphenyl)phenylmethane and the like are useful as a raw material for .alpha.-(m-benzoylphenyl)propionic acid (tradename: Ketoprofen) of a profen analgesic.
Hereby, as already described, the mixture comprising the o-ethyldiphenylalkane and the m-ethyldiphenylalkane can be industrially produced in low cost utilizing an alkylation reaction, a disproportionation reaction, a condensation reaction and the like in the presence of an acid catalyst from an alkylbenzene and the like.
Therefore, if 1-(m-vinylphenyl)-1-phenylethane, 1-(m-vinylphenyl)-1-phenylethylene, (m-vinylphenyl)phenylmethane and the like can be obtained utilizing the mixture, it is industrially advantageous.
However, anethyldiphenylalkane is obtained as a mixture comprising an o-ethyldiphenylalkane, a m-ethyldiphenylalkane and a p-ethyldiphenylalkane by the process utilizing an alkylation reaction, a disproportionation reaction, a condensation reaction and the like in the presence of an acid catalyst from a raw material such as an alkylbenzene or the like.
The boiling points of o-, m- and p-(ethylphenyl)phenylmethane are 290.9.degree. C., 291.5.degree. C. and 297.0.degree. respectively. In addition, the boiling points of o-, m- and p-1-(ethylphenyl)-1-phenylethane are 285.degree. C., 284.degree. C. and 293.degree. C.
Accordingly, in case of a p-ethyldiphenylalkane, the p-ethyldiphenylalkane can be separated by a usual separation method of distillation from a mixture of ethyldiphenylalkanes containing thereof.
However, it is practically difficult to separate a m-ethyldiphenylalkane from a mixture comprising an o-ethyldiphenylalkane and a m-ethyldiphenylalkane by distillation. Therefore, it is considered the process of using the mixture comprising the above-mentioned o-ethyldiphenylalkane, m-ethyldiphenylalkane and p-ethyldiphenylalkane as a raw material is difficult to be industrially adopted. In fact, such proposal is not proposed yet.